1. Field of the Invention
This invention is directed to novel processes for preparing intermediates which are useful in the synthesis of glycopeptide antibiotic derivatives. More specifically, this invention is directed to processes for preparing β-amino aldehyde compounds in which the amino group is blocked with an amino-protecting group.
2. State of the Art
Glycopeptides (e.g. dalbaheptides) are a well-known class of antibiotics produced by various microorganisms (see Glycopeptide Antibiotics, edited by R. Nagarajan, Marcel Dekker, Inc. New York (1994)). These complex peptide compounds are highly effective antibacterial agents useful for treating infections caused by Gram-positive bacteria.
For example, International Publication Numbers WO 00/39156; WO 01/57071 A2; and WO 01/98328 A2 disclose novel glycopeptide derivatives having antibacterial activity. These publications also discloses the use of N-protected β-amino aldehyde compounds, such as N-FMOC-2-(n-decylamino)acetaldehyde, as intermediates in the preparation of such glycopeptide derivatives.
The N-protected β-amino aldehyde compounds disclosed in these publications are prepared in several steps, with the product from each step being isolated separately before the next step. The final step of the disclosed process is an oxidation of the corresponding alcohol using an oxidizing agent, such as sulfur trioxide or oxalyl chloride and dimethyl sulfoxide. Unfortunately, these oxidizing agents produce a unpleasant odor during the reaction process and leave a residue odor in the final product. Accordingly, a need exists for new processes for preparing N-protected β-amino aldehyde compounds.